MusCL has the short term goal of conforming to the ANSI X3J13 specification somewhat portably (Windows, SUSV3). The long term goals include multiple dispatch implemented in the way Weimin Chen and Volker Turau thought up and Karel Driesen, Urs Höltzle and Jan Vitek carried on (fast, funny lookup tables), native threading and a good garbage collector. I haven't selected one yet.